This invention relates to rotary valves which permit quick and easy disassembly and access to the interior of the valve for inspection, seal maintenance and cleaning without requiring the removal of the valve from the installed position. The invention further relates to rotary valves which are useful in handling food stuffs or materials which will not tolerate cross-batch contamination, such as when colors must be frequently changed. The invention further contemplates a shaft seal assembly for such a rotary valve.
In many rotary valve applications, frequent cleaning of the internal valve parts is required; particularly, in those applications which require the handling of a food stuff or materials which will not tolerate cross-batch contamination. To achieve a thorough cleaning of all internal valve surfaces, it has been necessary in the past to completely disassemble the valves. Existing rotary valve designs do not provide a means for quick removal of the seal for cleaning, inspection and replacement. Seals are normally located between a bearing and the device with limited space for access to the seal, making seal removal very difficult. Frequently the seal is destroyed when removed because of the limited workspace.
More particularly, seals in the past have consisted of braided packing, Chevron packing or the like which are held in place by a close fit between the outer diameter of the seal and the inner diameter of the seal housing. The shaft rotates and the seal is stationary with sealing occurring between the seal inner diameter and the shaft outer diameter. This design does not permit the seal to be removed and replaced as an assembled unit.